Heat stability of zearalenone in an aqueous buffered model system

Zearalenone is an endocrine disruptor with estrogenic activity, produced primarily by Fusarium graminearum, a common cause of corn ear rot and Fusarium head blight or scab in wheat. Zearalenone can be a contaminant of both corn and wheat and may survive thermal food processes. This study was done to determine the heat stability of zearalenone. Reduction of zearalenone was measured during heating at different temperatures (100, 125, 150, 175, 200, and 225 degreesC) in an aqueous buffer solution at different pH values. The rate and extent of zearalenone reduction increased with processing temperature. Less than 23% of zearalenone was lost when heated to less than or equal to125 degreesC whereas 34-68% was lost at 150 degreesC after 60 min, depending on the pH of the buffer. Greater than 92% of zearalenone was lost after 60 min when heated to greater than or equal to175 degreesC, and complete reduction of zearalenone was observed in less than 30 min at 225 degreesC, regardless of pH. Overall, zearalenone was most stable at pH 7 followed by that at pH 4 and 10, and the greatest losses occurred above 175 degreesC.